In clinic, simplified mandibular movement measuring devices are used for diagnosis of patients with stomatognathic dysfunction and recording maxillomandibular relation. It is difficult to understand mandibular movement in three dimensions from the path on the three planes, because the path of mandibular movement is in three dimensional space with time, not separately on each plane. The purpose of this study was to develope the three dimensional analyzing system by computer graphics. Mandibular movement was recorded by Mandibular Kinesiograph. The signals were sent to personal computer and the data were processed by the software. The basic specifications of the program were as follows:
1. Data could be observed from various viewpoints.
2. Necessary section of the simultaneous data could be displayed.
3.“C” was used for the software describing language.
Following results were obtained:
It was possible to analyze the path of mandibular movement in other coordinate axis and understand the path of mandibular movement in three dimensions more accurately.

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Influence of a repetitive commanded acoustic signal with constant frequency of 1.3 Hz on jaw tapping movement was studied. 10 healthy subjects were made to perform anticipated jaw tapping movement corresponding to the signal. Jaw tapping movement with and without signal were analyzed for their opening distance and a ratio of duration of opening phase I (depressing phase), opening phase II (plateau phase), closing phase and tooth contact phase to the cycle time.
1. Opening distance in loaded tapping was shorter than that in the tapping ad lib.(P≈0.01), and independently of commanded signal it became to be longer with increasement of trial numbers (P≈0.01).
2. The ratio of duration of tooth contact phase in loaded tapping became smaller with increasement of the trials, although that in the tapping ad lib. became greater (P<0.001).
3. The ratio of duration of opening phase I in loaded tapping became greater with increasement of the trials, while that in the tapping ad lib. became smaller (P≈0.01).
4. It could be interpreted that in the loaded tapping “an instant performance controll” acted from the beginning of the trials and the signal might make it facile or easy to detect and confirm errors in movement.

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In this study, the relationship among the chemical composition and the physical and chemical properties of four photo-cured composites and one heat curing composite for crown and bridge were investigated.
Five composites were composed of the base monomer, UDMA, TriEGDMA, 1, 3-BDMA, 1, 4-BDMA, 1, 10-DDMA, 1, 12-DDDMA or those mixture, and the composite-filler consist of the resin (TMPTMA, UDMA, 1, 10-DDMA or 1, 12-DDDMA) and micro-silica particles.
Four photo-curing composites had a high elastic modulus and Vickers hardness and a low thermal expansion coefficient and water sorption compared with the heat-cured composite (Is).
The effects of filler contents in the composites examined were positively on the elastic modulus and the hardness, and were inversely on the bending strength and the thermal expansion coefficient of the cured products. While the organic phase in the composite fillers had effect on the abrasive resistance of the composites. But no significant correlation between the abrasive resistance and the filler contents and the physical properties of the materials tested was noted.

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The following results were obtained from studying the removability of 53 removable partial dentures.
1. All of their retentive forces were less than 2, 000 gf.
2. In 5 out of 31 dentures whose retentive forces were graded D2 and less, the wearers could remove the dentures easily without help of their fingers. Out of 22 dentures graded D4 and more, 3 conic dentures were difficult in removal.
3. The wearers were dissatisfied with 3 dentures graded D2 and less, and with 2 conic dentures graded D4.
4. In 12 dentures graded D1, 9 dentures were evaluated to be too loose by the operators. In 12 dentures graded D4 and more, 2 conic dentures were evaluated to be too tight by both the wearers and the operators.
5. All conic dentures complained had 4-degree-tapered conic studs as the retainer.
6. It is considered that in terms of subjective evaluations, an adequate retentive force for the dentures might be in the range from 800 gf to 2, 000 gf.

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The interaction of Hydroxyapatite (HAP) with organic molecules is biologically important. Some proteins display a high adsorption affinityfor HAP and they have been implicated in the mineralization of bone. In order to undersand the interaction of HAP with proteins, it is important to know which amino acid side-groups are involved in the protein-HAP interaction and what type of interaction takes place.
We investigated the interaction of HAP with amino acids and their derivatives by crystal growth experiment. The rate of crystal growth was measured by adding seed crystals of HAP (synthetic apatite) to a solution of CaCl₂ and KH₂PO₄, pH 7.4 at 37°C. Basic amino acids, acidic amino acids and amino acids with polor side-groups inhibit the rate of crystal growth.
These findings suggest that amino acid side-groups, such as carboxyl group, amino group, hydroxyl group and imidazole, are related to the affinity for HAP.

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It is important to clarify the relationship between prosthetic appliances and periodontal tissues for ideal prosthetic restorations. And therefore objective methods which give proper diagnosis for the first stage of gingivitis areindispensable.
The purpose of this study was to investigate, using Periomicroscope, alterations of the blood vessels beneath the oral sulcular epithelium during ahuman experimental gingivitis, and to establish relationship between observation by Periomicrpscope and clinical and histologic findings on the first stage of gingivitis.
The subjects were 22 student volunteers ages 20-29 years with clinically normal periodontal tissues. At upper anterior teeth, gingivitis was produced by withdrawing tooth brushing for 21 days.
After 21 days clinically nearly moderate gingivitis and histopathologically nearly moderate chronic gingivitis were observed, while significant differences were obtained in the changing of the capillary loop form.
From the results obtained by Periomicroscope, it was suggested that the continual observation by Periomicroscope was effective for the diagnosis of gingivitis.

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The endosseous dental implants of glass-ceramic were implanted and holles were drilled as control in edentulous areas of adult dog mandibles. The implants were kept without function. After 2-84 days, the biological reaction of the tissue was examined by histological and ultrastructural methods, while the glass-ceramic surface was examined by EPMA analysis and X-ray diffraction.
The results were as follows:
1. After 4 days the bone matrix formation started on the surface of the glass-ceramic. After 14 days, the area of bone formation on the implant surface was enlarged and about all surface was covered with this woven bone.
2. Being compared with the control, glass-ceramic didn't prevent the healing process of bone.
3. On the surface of glass-ceramic, apatite and β-whitlockite crystal formation was observed by X-ray diffraction. And analysis by EPMA showed this areas combined bone.
4. TEM observation showed that there were many hemidesmosomes in interface between the implant and attached epithelium. In the subepithelial fibrous tissue collagen fibers and fibroblasts were arranged in parallel on the implant surface.

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This study was executed at an opportunity for taking the impressions of a full crown abutment tooth by the five different methods with the four different impression materials; the copper ring tray on the abutment method with the polysulfide rubber, the resin ring tray on the abutment method with silicone rubber, the wash technique with silicone rubber, the hydrocolloid impression technique and th hydrocolloid-alginate impression technique.
The reproducibility of the preparation margin on the ten stone dies was photographically measured and the following results were obtained.
1. The reproducibility of the preparation margin was affected considerably by the following conditions. 1) The character of the impression materials, 2) the position of the preparation margin in the gingiva sulcus and 3 the undercut degree beneath the preparation margin.
2. The impression technique with the individual ring tray on the abutment showed great utility under any condition of the preparation margin on the abutment.
3. The impression method should be selected clinically according to the condition of the abutment.

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Antibacterial action of various denture base resins on thirteen species of bacteria were studied in vitro. Antibacterial effect of 5% tannin-fluoride preparation, 5% tannic acid and 5% chlorhexidine added to resins on these thirteen bacterial species were also investigated using heat-curing denture base resins.
Fresh microwave-curing resin and pour-type resin each showed an antibacterial action on one bacterial strain. Fresh self-curing resins had antibacterial actions on serveral bacterial strains. However, after storage in water at 37°C for one week, antibacterial action of microwave-curing and pour-type resin were diminished and self-curing resins partially lost their antibacterial actions.
Denture base resin containing tannin-fluoride preparation or tannic acid showed an antibacterial effect on one bacterial strain. On the other hand, denture base resin containing chlorhexidine had an antibacterial action on eleven bacterial strains. However, color and mechanical properties of the drug-containing resins were not satisfactory.

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The metals for porcelain fusing used in this study were gold alloys and nickelchromium alloys. Chromatic characteristics were compared between samples of 0.1, 0.2 and 0.3mm thickness. The dentin porcelain was fused on the opaque surface. Chromatic analyses were then carried out at each stage of 0.1mm-incremental reductions of the dentin thickness starting from 0.5mm.
In conclusion, the metallic color was not sufficiently hidden by opaque porcelain 0.1mm thick for both the gold alloy and nickel-chromium alloy samples. The metallic color was sufficiently hidden by opaque porcelain of 0.2mm thick for the gold alloy sample but was not sufficiently for the nickel-chromium alloy sample.

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We proposed a new optical system to measure the movements of less accessible organs with soft tissue. The sensor unit is composed of a phototransistor and two LEDs. Two LEDs of light sources are driven by two phase signals with phase shift of 90°. The distance between the sensor and the measuring object can be obtained as the function of the phase angle of reflex light signal detected by the phototransistor. The system can be easily constructed and provides simultaneous recordings of multiple points with the fast response in real time. The Relative precision is 0.5mm and the resolution is 0.05mm. Output characteristic of the system was less affected by the reflection factor of the object. We conducted to observe the tongue movements in speech production.

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Wire clasps and cast clasps are the most common retainers for removable partial dentures. The purpose of this study was to investigate the differences in the material and the variation among individual technicians in the retentive force of both clasps. The clasps were made in accord with the clinical method for experimental metalic model of the left mandibular second premolar and the retentive force of each clasp was measured by a pull-out test.
The results were as follows:
1. Both types of clasp showed a large variation in the retentive force among the technicians, but no particular tendency was observed in the differences between wire and cast clasps.
2. There was no significant difference between the two types of clasp in the retentive force.
3. Due to the differences in individual technical skills, it seems to be difficult to make wire clasps with a standardized retentive force.

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The purpose of this study is to estimate objectively temperature changes of palatal mucosa after denture wearing.
Temperature at 7 measurement points of palatal mucosa in 10 normal dentate subjects were measured to determine the time constant by carrying out a least square approximation of the relation between temperature and time from the time of commencement of temperature measurement until the time of temperature elevation to a steady state. Changes in the time constant by thermal stimulation with cold and warm water and by wearing of an experimental palatal plate were studied.
It was found that if the time constant is obtained from values measured at 60-second intervals, the predicted and measured values of steady-state temperature are well approximated and that the time constant is significantly reduced from 3 days after wearing of an experimental palatal plate and is significantly increased (prolonged) from 3 days after thermal stimulation.
These results demonstrated that temperature changes of the palatal mucosa during the use of a removable denture can be subjectively and quantitatively estimated with accuracy on the basis of the time constant obtained by least square.

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Reconstruction of the crowns of non-vital teeth with posts can be a very useful technique.
However, there are many cases where the length of the posts are insufficient, resulting in a poor fit and dead space at the apex of the post.
The purpose of this study was to compare the post length to the depth of the post preparation using palallel X-ray films of 31 teeth (incisors, canines and premolars) and to locate the dead space at the apex of the post. In addition, stress analysis of the post-reconstructed upper central incisor models having five types of posts with dead space at the apex and two levels of supporting conditions were calculated using the finite element method.
The results obtained were as follows:
1. From the roentogenographic survey, the depth of the post preparations averaged two thirds of the remaining root length, and one half the length of the root in bone. However, lengths of the posts were on the average 20% shorter than the depth of the post preparation.
2. As the dead space increased and supporting levels diminished, stresses of post-reconstructed teeth were found to increase gradually and to concentrate in the remaining dentin near the apex of the post.

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Previous study found that ion coating treatment with Cu target demanded 10 minutes of treatment to achieve the durable adhesion with 4-META resin. For clinical application, it's indispensable to shorten the treatment period. Sn and Cu-Sn target were examined in this study.
4 minutes of treatment with Sn target showed high bond strength of adhesion. However, the excess of treatment time over 8 minutes caused the remarkable decrease of adhesion durability against thermal cycling.
In clinical situation, many of the prosthesis possess the wings of complex shape and it's difficult to attain the uniform coating by only once treatment. However, the repetition of treatment with Sn target is undesirable because of the decrease of adhesion durability.
Favorable result was shown by 4 minutes of treatment with Cu-Sn target and even by 30 minutes of treatment, same result was attained.
With this ion treated specimens of Au-Ag-Pd alloy sandblasted, the adhesive bond strength of above 200kgf/cm² was maintained after 100, 000 thermocycles.

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Measurements have been made on the tongue contact area of the palate and maxillary teeth during pronunciation of /sa, ∫i, ci, ka, ki, ta, na, ra, ja/(palatogram). The subjects were 30 dentulous adults (21 men, 9 women). The artificial palates made of black vinyl seat covering the palate and occlusal surfaces of maxillary teeth were coated with white alginate powder and inserted into the mouths of the subjects. After pronunciation of the test sound, the tongue contact areas on artificial palate were demonstrated by wetting of powder and changing in color from white to black. Thus photographs of the palatograms were taken.
An image processor system was employed for averaging each subject's 5 samples of same sound. The averaged outline of each subject's palatograms were converted to the standardized dental arch form and added and stored into frame memory. The 60-90% of subject's common parts were extracted from the added palatograms of same sound and illustrated in different gray levels.
The results indicate that the tongue-to-teeth contact area of each sound differ from the others, however, it's range is confined within cervical half of lingual surface of incisors and lingual cusps of molars.

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The purpose of this study was to investigate electromyography of the inferior heads of lateral pterygoid muscles in experimental displacement of mandible, and its clinical application for reproduction and diagnosis of mandibular position. In the experiments, the mandibular position was changed in vertical and horizontal directions and muscle activity of the inferior heads was analyzed quantitatively.
The results obtained were as follows:
1. Muscle activity of inferior heads was increased with amount of the displacement in anterior direction, and reached to great increase in 1.0 mm and 2.0 mm displacement of mandible.
2. No definite tendency of ipsilateral inferior heads was shown in lateral displacement of mandible.
3. Muscle activity of contralateral inferior heads in lateral displacement was increased with amount of the displacement, and 3 muscles showed great increase in 1.0-2.0 mm displacement of mandible.
4. As vertical increase was less than 2.0 mm, muscle activity of the inferior heads was decreased as to that of intercuspal contact position.
5. Muscle activity of the inferior heads in retruded position showed a little increased, but evidently as to that of intercuspal contact position.
6. Increasing patterns of muscle activities in anterior displacement were different from in contralateral displacement.
7. In anterior mandibular position an ability of presuming a mandible displacement over the limits of 1.0 mm from intercuspal contact position was suggested using muscle activity of inferior head as an index, and in lateral mandibular position that over the limits of 1.5 mm suggested.

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The purpose of this study was to investigate the acoustic characteristics of thenine sounds, /sa/, /si/, /ka/, /ki/, /ci/, /hi/ and /ri/, which were reported affected by wearing complete denture, through the acoustic analysis of speech samples uttered by nine male subjects.Spectrum analysis was done within the frequency range of 0 to 10 KHz according to the auto-correlation method of liner predictive coding (LPC) analysis.
Results
1. The consonant parts of isaf, /si/, /ci/ and /hi/ were characterized by the spectrum envelopes and their peak frequencies derived from the LPC analysis of order 5.
2. The consonant parts of /ka/ and /ki/ were characterized by their first spectrum peak frequencies derived from the LPC analysis of order 10.
3. The consonant part of /ri/ was characterized by the spectrum envelope derived from the LPC analysis of order 24, and the sound waveform.
4. The frequencies of the formants (F 1, F 2, F 3) of the following vowels / i / were derived from the LPC analysis of order 24. They were influenced by individual variations and preceding consonants.
5. Each sound had its own characteristics in the duration of the consonant and of the closure interval and the time from the end of preceding vowel to the beginning of the following vowel.

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Inflammatory responses in periodontal tissues cause breakdown of normal protein metabolism. The biochemical analysis of the protein components in gingival crevicular fluid (GCF) which is exudate from periodontal tissues offers a sensitive means of determining periodontal disease activity of abutment teeth. GCF proteins were applied to the high performance liquid chromatography (HPLC) analysis with following conditions:(1) column: an anion exchanger, (2) starting buffer: 20 mM tris HCl pH 8.5, (3) elution buffer: 20 mM tris HCl with 1 M NaCl pH 8.5, (4) gradient of NaCl concentration: 0-0.5 M=20 min., 0.5-1 M=5 min., (5) flow rate: 1 m//mm. 12-15 peaks were observed in HPLC chromatograms, they were then divided to 6 fractions and were qualitatively analysed with agarose IEF, IEP and 2 DPAGE. Determined main protein components in each peak were IgG (peak 1), transferrin and hemopexin (peak 2), C′ 3 and IgA (peak 3), Albumin, C′ 3, IgA, IgM, Haptoglobin, a2-macroglobulin and α1-antitrypsin (peak 4), respectively. Those protein components were thought to be closely related to periodontal inflammation. It was suggested that the activity of periodontal disease was evidenced by observation of HPLC chromatogram on GCF proteins.

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The purpose of this study was to determine the degree of restoration of masticatoryfunction with fixed molar bridges. Evaluations were made of the deep temperature of themasseter muscle, masticatory performance and occlusal contacts (duration, force distribution, area and number of contacts).
Criteria were established for the parameters above mention in 30 normal subjects.
Fixed bridges were placed in 10 patients with missing only the mandibular first molar.Measurements were carried out both prior to and after placement of the prosthesis.
The following results were obtained.
1. The deep temperature of the masseter muscle patients recovered in 30 days after prosthesis.
2. The total number of contact points and contact area increased after placement by 30days.
3. The duration of occlusal contacts increased up to 30 days after placement.
4. The force distribution of occlusal contacts decreased for a time but recovered as thenormal subjects after 30 days.
5. The masticatory performance was restored immediately after the placement and showed no change by 45 days.

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The muscle fiber conduction velocity is used as an indication of a localized muscular fatigue or some muscular diseases. The purpose of this study was non-invasively to estimate the conduction velocity of the human masseter muscle using surface electrode arrays. Informed consent was obtained from a group of 8 healthy subjects (24-27 yr) without functional, disturbances of the jaws and with natural dentitions. Each subject was asked to perform a brief isometric contraction at 10, 20, 30, 40 and 50% of the maximum EMG amplitude and an endurance of 30 and 50% MVC in the intercuspal position. The myoelectric potential was derived from an adjacent pair of electrode wires and the velocity was estimated by the electrode distance divided by the time delay between two myoelectric signals. The time delay was calculated by the cross-correlation technique.
The results obtained were as follows, :
1. The muscle fiber conduction velocity slightly increased with contraction force.
2. The exponential reduction in velocity was shown during fatiguing contraction of 50%MVC.
3. The muscle fiber conduction velocity decreased with the time after fatiguing contraction.
4. It was suggested that the conduction velocity of the muscle membrane discharge was an important index of muscular fatigue.

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Microvascular changes of the denture-bearing mucosa on the hard palate of Japanese monkeys (Macaca fuscata) were investigated on microvascular casts utilizing the acryl plastic injection method (Taniguchi, Ohta et al. 1952, 1955) under SEM and ultrastructure of the endothelium of the blood capillary and surrounding tissues under TEM.
The results obtained were as follows:
1. SEM findings of microvascular casts were by 10 days after setting the experimental denture capillary loops appeared a simple hair-pin shape. By 30 days the loops changed into a kind of sinusoidal networks. By 60 days the loops of the network began to sort out and to reform into hair-pin shape.
2. Aspects under the light microscope and SEM were essentially similar to those of its serial changes of the capillary loops.
3. Aspects under TEM were fenestrated capillaries have altered to continuous ones after 10days, and again reformed to the fenestrated capillaries by 60 days.
From the above results, it can be said that, although the subepithelial microcirculatory system is temporarily affected by the placement of an experimental denture, it may adapt itself to the mechanical stress of the pressure and so before recovering.

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Fifty years ago, dentists had always used modelling compound to take functional bite pattern as a method for making the occlusal surface of a crown in order to simplify the final occlusal adjustment. Therefore, the writer adopted the same method to fabricate crown bridge with inlay wax and to construct denture with paraffin wax. The results achieved the same simplification during occlusal adjustment procedure.

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The pure titanium cast frameworks were made using an arc-melting pressure and vacuum casting apparatus invented by Sato, and an experimental investment material. The salient features of the method and the cast frameworks were as follows:
1. The casting apparatus used was capable of making both complete and partial denture frameworks with pure titanium. It reduced casting errors and the interaction between titanium and the casting mold, producing less porous casted frameworks with a smooth surface.
2. The experimental investment material made a firm heat-resistant investment model with a smooth surface. It showed appropriate expansion and also excellent strength at room temperature after the burn out of the wax pattern.
3. The titanium casted frameworks fitted to the model and the oral cavity closely, and yielded satisfactory clinical results in more than 15 patients.Key words: pure titanium, denture framework, investment, castability, casting porosities

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